Process for the preparation of monohalogenated methylenediphosphonate esters, and phosphonoacetate esters

ABSTRACT

A process for the preparation of tetrahydrocarbyl monohalomethylenediphosphonate esters, dihydrocarbyl monohalomalonate esters and trihydrocarbyl monohalophosphonoacetate esters, wherein the hydrocarbyl groups have one to 22 carbon atoms, comprising reacting the corresponding dihalomethylenediphosphonate esters, dihalomalonate esters and dihalophosphonoacetate esters with a reducing agent, e.g., sulfite ion in base or sulfide ion in base. The monohalomethylenediphosphonate esters, monohalomalonate esters and monohalophosphonoacetate esters are useful as intermediates in the preparation of detergency builders for use in detergent compositions and as extreme pressure additives and antiwear additives in lubricant compositions.

United States Patent [72] Inventor Denzel Allan Nicholson Springfield Township, Hamilton County, Ohio [2i Appl. No. 786,760

[22] Filed Dec. 24, 1968 [45] Patented Dec. 14, 1971 [7 3] Assignee The Proctor & Gamble Company Cincinnati, Ohio [54] PROCESS FOR THE PREPARATION OF MONOHALOGENATED METHYLENEDIPHOSPHONATE ESTERS, AND PHOSPHONOACETATE ESTERS 18 Claims, No Drawings U.S. Cl 260/986, 260/485, 260/932, 260/941 C07f 9/40 260/986 References Cited OTHER REFERENCES Wiley & Sons, lnc., New York 1963) page 8.

Primary Examiner-Charles B. Parker Assistant Examiner-Richard L. Raymond Attorneys-Waddell A. Biggart, Richard C. Witte and Robert B. Aylor ABSTRACT: A process for the preparation of tetrahydrocarbyl m0nohalomethylenediphosphonate esters, dihydrocarbyl monohalomalonate esters and trihydrocarbyl monohalophosphonoacetate esters, wherein the hydrocarbyl groups have one to 22 carbon atoms, comprising reacting the corresponding dihalomethylenediphosphonate esters, dihalomalonate esters and dihalophosphonoacetate esters with a reducing agent, e.g., sulfite ion in base or sulfide ion in base. The monohalomethyienediphosphonate esters, monohalomalonate esters and monohalophosphonoacetate esters are useful as intermediates in the preparation of detergency builders for use in detergent compositions and as extreme pressure additives and antiwear additives in lubricant compositions.

PROCESS FOR THE PREPARATION OF MONOIIALOGENATED METHYLENEDIPHOSPHONATE ESTERS. AND PHOSPI'IONOACETATE ESTERS BACKGROUND OF THE INVENTION This invention relatesto a process for the preparation of monohalogenated methylenediphosphonate esters,

. monohalogenated malonate esters, and monohalogenated PRIOR ART Halogenated derivativesof methylenediphosphonic acid and the corresponding tetrahydrocarbyl methylenediphosphonate esters (hereinafter methylenediphosphonates), of the dihydrocarbyl malonate esters (hereinafter malonates), and of the trihydrocarbyl phosphonoacetate esters (hereinafter phosphonoacetates) are known in the art. While these compounds have been described in the literature, feasible methods of synthesizing the halogenated derivatives have been most difficult to develop. Several methods of replacing an active hydrogen on a bridging carbon with a halogen atom are known in the art by which the halogenated derivatives might conceivably be synthesized. These heretofore known synthesis routes, e.g., direct halogenation, result in low yields and often involve side reactions which hamper the completion of the desired reaction. The known synthesis routes are impractical, expensive, and require the use of elevated temperatures. Such halogenation methods seldom result in yields of the halogenated derivatives greater than about 25 percent. .An additional disadvantage of prior art processes is that mixtures of monohalo and dihalo derivatives are obtained. Thus, special problems are created where substantially pure monohalo methylenediphosphonate, malonate, or phosphonoacetate is desired. For example, the similarity in properties of the monohalo and dihalo derivatives of these compounds makes quantitative separation by conventional techniques impractical.

The copending application of John D. Curry, Ser. No. 770,805, filed Oct. 25, 1968, for Hypohalogenation of Tetramethyl and Tetraethyl Methylenediphosphonates and Trihydrocarbyl Phosphonoacetates, discloses a practical method for the production of halogenated methylenediphosphonates (C,C,) and phosphonoacetates (C -C.) which minimizes some of the difficulties above enumerated. The Curry application discloses a process comprising reacting a tetramethyl or tetraethyl methylenediphosphonate or a trihydrocarbyl phosphonoacetate with hypohalite ion in an aqueous electrolyte solution, preferably in the presence of an inert waterimmiscible organic solvent, to produce the corresponding monoand dihalogenated methylenediphosphonates or phosphonoacetates. While this process is an improvement over prior art methods and satisfactory for the preparation of mixtures of monohalo and dihalomethylenediphosphonates or phosphonoacetates, or the dihalo derivatives of these compounds alone, it is not a feasible route to the synthesis of pure monohalomethylenediphosphonates or monohalophosphonoacetates in quantitative yields. in fact, as explained above, separation of the monohalo derivative from the dihalo derivative, which is produced to some extent by the process described by Curry, supra, is expensive and time consurning.

The copending application of Oscar T. Quimby and James B. Prentice, Ser. No. 707,782, filed Oct. 25, 1968, for Hypohalogenation of Gem-Diphosphonate Esters and Phosphonoacetate Esters, discloses a second method of and phosphonoacetates (C -C In the method described therein a methylenediphosphonate or phosphonoacetate ester is reacted with hypohalite ion in an aqueous solution containing electrolyte to produce the monohalogenated or dihalogenated methylenediphosphonates or monohalogenated or dihalogenated phosphonoacetates. Although the process described by Quimby et al., above is an improvement over prior art methods of synthesis, the monohalomethylenediphosphonates and monohalophosphonoacetates cannot be obtained in high yield in a pure form.

The copending application of Denzel Allan Nicholson, Ser. No. 770,860, filed Oct. 25, 1968, for Process for the Production of Halogenated Methylenediphosphonates, Malonates and Phosphonoacetates, also discloses a process for the preparation of monoand dihalogenated methylenediphosphonates (C C,,), malonates (C.C and phosphonoacetates (C -C comprising reacting a methylenediphosphonate, malonate or phosphonoacetate ester with hypohalite ion in a two-phase reaction system composed of an aqueous solution and/or a water-miscible organic solvent with no added electrolyte and an organic phase containing the methylenediphosphonate, malonate or phosphonoacetate ester. Again, as with the two hereinbefore cited processes for the production of halogenated methylenediphosphonate, malonate and phosphonoacetate esters, the process is an improvement over prior art synthesis routes but pure monohalomethylenediphosphonate esters, malonate esters or phosphonoacetate esters cannot be obtained in high yield.

Accordingly it is an object of this invention to provide a process for the preparation of tetrahydrocarbyl monohalomethylenediphosphonates (C -C dihydrocarbyl monohalomalonates (C,C and trihydrocarbyl monohalophosphonoacetates (C -C in very high yields. Additionally it is an object of this invention to provide a process for the preparation of tetrahydrocarbyl monohalomethylenediphosphonates, dihydrocarbyl monohalomalonates and trihydrocarbyl monohalophosphonoacetates which eliminates the necessity of using difiicult, costly and time consuming separation and purification techniques.

SUMMARY OF THE INVENTION This invention relates to a process of preparing tetrahydrocarbyl monohalomethylenediphosphonates, dihydrocarbyl monohalomalonates and trihydrocarbyl monohalophosphonoacetates in very high yield. The process comprises reacting an ester of the formula wherein A and B are selected from the group consisting of MR, and -CO,R, wherein each R is a hydrocarbyl group selected from the group consisting of alkyl, aryl, alkaryl, aralkyl, haloalkyl, haloaryl, haloalkaryl, haloaralkyl, alkenyl, haloalkenyl, and nitroaryl groups having from one to about 22 carbon atoms, and wherein each X is a halogen atom selected from the group consisting of chlorine, bromine and iodine;

with a reducing agent selected from the group consisting of sulfide ion in base, thiosulfate ion in base, hydrogen with a noble metal in base, phosphorous acid in base, formaldehyde in base, iodide ion in base, stannous ion, acetaldehyde, formic acid in base, cyanide ion in base, and sulfite ion in base, in an preparing the halogenated methylenediphosphonates (C -C equivalency ratio of reducing agent to ester of from about 3 0.9:1 to about i. l :1, said reducing agent being selected as follows:

1. when A and B both are -PO;, R and when each X is selected from the group consisting of chlorine, bromine plication, supra, and the Roy patents, supra, are incorporated herein by reference.

DETAILED DESCRIPTION OF THE INVENTION and iodine, the reducing agent is selected from the group 5 The process of this invention for the reduction of consisting 0f sulfide ion in base- Sulfile ion in base. dihalomethylenediphosphonate, dihalomalonate and lhiosulfaifi ion in base. y g with a noble metal in dihalophosphonoacetate, to the corresponding monohalo base, formic acid, in base, cyanide ion in base, derivative can be shown by the following schematic equation: phosphorous acid in base, and formaldehyde in base; 2. when A and B both are -co,R and when one x is selected from the group consisting of chlorine, bromine and iodine, and the other X is selected from the group i reducin sgent it consisting of bromine and iodine, the reducing agent is X T selected from the group consisting of iodide ion in base, 1s 2 B sulfite ion in base, stannous ion, acetaldehyde, sulfide ion 7 N 7 A i in base, thiosulfate ion in base, hydrogen with a noble metal in base, formic acid in base, cyanide ion in base, phosphorous acid in base, and formaldehyde in base; Where A and B each are --PO,R,, the tetrahydrocarbyl 3. when A and B both are CO,R and when both X's are dihalomethylenediphosphonates, as starting materials, are chlorine, the reducing agent is selected from the group described, with the tetrahydrocarbyl consisting of sulfite ion in base, and cyanide ion in base; monohalomethylenediphosphonates being formed according and to equation 1 below: 4. when A is CO,R and B is --PO R, and when each X is selected from the group consisting of chlorine, bromine and iodine, the reducing agent is selected from the group L P 03R? P 03R: consisting of stannous ion, acetaldehyde, sulfide ion in L reducing A base, sulfite ion in base, thiosulfate ion in base, hydrogen H10 1 with a noble metal in base, formic acid in base, cyanide wwgqifiu is m. 7 ion in base, phosphorous acid in base, and formaldehyde in base; said process being conducted in an a ueous solution at a temperature of from about 25 to about20 C. R X are as herembefore defined The monohalo derivatives of the methylenediphosphonates, ss gi z groups for R i g malonates, and phosphonoacetates, wherein the hydrocarbyl omet y i 05p (mate esters are as 0 CW5. met y ethyl, propyl, lso-propyl, butyl, pentyl, hexyl, heptyl, octyl, groups have from one to about 22 carbon atoms, are useful as extreme pressure additives in lubricant com ositions The decyl'dodecyltetradecylpentadecyL-hexadecy!hepmdecyl' monohalo methylenediphos honates mal znates and octadecyl' eicosyl' phenyl' naphthyl b1phenyl'(2-ethyl)hexyl phosphonoacetates wherein tii; h drocarb l mu has from pmpenyl' decenyl benzyl mcthylphenyl dodecylphenyl b b0 b y 2; g p 40 phenyldodecyl, oleyl, 7-chlorohexyl, l5-1odopentadecyl, 9- a a f on atoms" f so useful as fluorononyl, (bromoethyDphenyl, p-chlorobenzyl, and pwear additives m lubricant compositions. The use of the nitrophenyl. flydrocwbyl groups such as alkyl aryl, malkyl. monohalo methylenedlphosphonates' f alkaryl and alkenyl groups are preferred because of their phosphonoacetates as extreme pressure additives and as am: ready availability. Ethyl, propyl' ismpropyl butyl, pentyl and wear additives in lubricant compositions, e.g., when used at phenyl are especially f d x is bromine, h i d about the 5 percent level in a Kendall base SAE 30 mineral idine Bromine is tz oil) is disclosed in the copending application of Robert Earl S ifi examples f h h dm b l Denlal Allan Nicholsonand Ted g monohalomethylenediphosphonates which can be prepared 762:9}56, filed P 1968, Lubricant Composition In by the process of this invention, as schematically described by addltlcfl i mOnohalomethylenediphosphonates are useful as equation I, and specific reducing agents which can be used to synthetic intermediates in the preparation of methane hydro effect the conversion of the corresponding dihalo derivative ydiphosphonate, a useful and effective alkaline builder salt for are shown in table I, e.g., by reaction of the dihalo derivative use in detergent compositions as disclosed by in U. S. Pat. No. shown in column (A) with the reducing agent shown in 3,422,021 issued Jan. I4, 1969 and Clarence H. Roy, in U. 8. column (B) to obtain the monohalo derivative shown in Pat. No. 3,404,178, issued Oct. 1, 1968. The Wann et a1. ap- 5 column (C).

TABLE I (A) (B) (O) Tetrahydrocarbyl dlhalomethylenediphosphonate Reducing agent Tetrahydrocarbyl monohalomethylenediphosphonate 'Ietramethyl diiodomethylenediphosphonate NazS/NaOH Tetramethylmonoiodomethylenediphosphonate. Tetraethyl dibromomethylenediphosphonate NazSzOaINaOH Tetraethyl monobromomethy]enediphosphonate. Tetrapropyl diiodomethylenediphosphonate. Fonnie aeid/KOH 'Ietrapropylmonoiodomethylonediphosphonate. Tetra-iso-propyl dibromomethylenediphosph NaC INaO i Tetra-iso-propyl monobromomathylenediphosphonate. Tetrabutyl dibromomethylenediphosphonate Hz(Pt)NaOH Tetrabutyl monobromomethy]enediphosphonate. Tetrapentyl dichloromethylenediphosphonat Formaldehyde/NaOIL Tetrapentyl monoehloromethylenedlphosphonate. Tetrahenyl diehloromethylenedlphosphonate Formio a d/KO Tetrahexyl monochloromethylenediphosphonate.

Tetrahepty monobromomethylenediphosphonate.

Ca(0 )2. Tetraoctyl dichloromethylenediphosphonate i NazS/CMOHM... Tetraoctyl monochloromethylenediphosphonate. Tetranonyl diiodomethylenediphosphonate. azSzOs/NHHCO: Tetranonyl monoiodomethylenediphosphonate. Tetradecyl diiodomethylenediphosphonate azS/KOH Tetradeeyl monolodomethylenedlphosphonate. Tetraundecyl dichloromethylenedlphosphonatg- Formaldehyde/N940 'Ietraundecylmonochloromethyienediphosphonate. Tetradodecyl dibromomethylenediphosphonate KzSzOi/CMO )2- 'Ietradodecyl monobromomethylenediphosphonate. Tetratridecyl diiodomethylenediphosphonate KzS/Ca(OH)z 'letratridecyl monoiodomethylenediphosphonate. Tetratetradecyl dibromomethy]enediphosphonatc NaON(NaOI-I Tetratetradecyl monobromomethylenediphosphonate. Tetrapentadecyl dichloromethylenediphosphonate Forma dehyde/NaOH Tetrapentndecylmonochloromethylenediphosphonate. Tetrahexadecyl dilodomethylenediphosphonate Fonnaldehyde/KOH Tetrahexadecylmonoiodomethylenediphosphonate. Tetraheptadeeyl dibromomethylenediphosphonate A Female acid/Oa(OH)z Tatraheptade 'yl monobromomethylenediphosphonatn. Tetraoctadecyl dibromomethylenediphosphonate NazSOa/NalICCH. 4 Tetraoctadccyl m0nobromomethylenediphosphonatc. Tetranonadecyl dichlorOmethylenedlphosphonate NazS/N H4011... Tetranonadeeyl monochloromcthylenediphosphonute. 'Ietraeicosyl diiodomethylenediphosnhonste KCN/CMOIDL Ectracicosyi monolpdomnthylpnediphosphonate.

schematically described by equation ll, and specific reducing propyl, iso-pnopyl, butyl, pentyl, hexyl, heptyl. octyl, decyl, agents which can be used to effect the conversion of the eordodecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, oc-

responding dihalo derivative are shown in table ll, e.g., by tadecyl, eicosyl, phenyl, naphthyl, biphenyl, (2-ethyl)hexyl, reaction of the dihalo derivative shown in column (A) with the propenyl, decenyl, benzyl, methylphenyl, dodecylphenyl, reducing agent shown in column (B) to obtain the monohalo 5 phenyldodecyl, oleyl, 7-chlorohexyl, lS-iodopentadecyl, 9- derivative shown in column (C fluorononyl, (bromoethyl)phenyl, p-chlorobenzyl, and p- TABLE II Uiliydrmnirbyl dihalomalonate Reducing agent Dihydrocarbyl monolmlonmlonate UIIHHUIY! Huhlorumulonate Na SO INaOH Dimethylmonochloromalonnto. Methyl (llbromomulonatc NaI/NaOH Diethylmonobromonmlonuti-. l)l-lso-pr0pyl dilodomalonate Sl'lClz Di-iso-pi'opylmonoiodomulonnto. Dibutyl llichl0romalonatc NazSOg/NaOIL. Dibutyl monochloronlolonuti. Dipentyl dichloromalonate K SO;/KOH Dipcntyl monochloromalonatv.

Dihexyl monobrmnomulonntc. Diheptyl monolodonmlonato. Dioetyl monochloromalouatn. Dinonyl monobromomalonntc.

Dihexyl dibromomalonate. Diheptyl diiodomalonate Dioctyl dichlommalonate Dinonyl dibromomalonate.

SnFz iii i Dideoyl diiodomalonate NazSgO3/Na0IL Didecyl monoiodomalonate. Diundecyl diehloromalonate... KCN/KOI-I Diundeeyl monochloromaloimtc. Didodecyl diiod0malonate Formic acid/NILOIL. Didodecyl monoiodomalonate.

Ditridecyl monobromomalonate.

. Ditetmdecyl monoiodomalonate.

Dipentadecyl monochloromalonato. Dihexadecyl monochloromalonatc. NaCN/NaO H Diheptadecyl monobromomalonatc. KHS/KOH Dioctadecyl monobromomalonatc. Acetaldehyde Dinonadecyl monobromomalonatc.

Ditridecyl dibromomalonate... Ditetmdecyl diiodornalonate Dipentadecyl dichloromalonate- Dihexadecyl dlchloromalonate Diheptadecyl dibromomalonate Dioctadecyl dibromomalonste Dinonadecyl dibromomalonate Dieicosyl dichloromalonate K SOg/KOII Dieicosyl monochloromalonatfl. Didocosyl diiodomalonate S1101; Didocosyl monoiodomalonatc.

Methyl ethyl dichloromalonate K SO /K PO Methyl ethyl monochlorqmalonatfi- Propyl pentadecyl diiodomalonate KI KOH Propyl pentadecyl monolodomalonatfl- Diphenyl dichloromalonate NQ SO INQOH Diphenyl monochloromalonate. Dinaphthyl dibromomalonate NaI/NH OH Dinaphthyl monobromomalonate. Dibiphenyl diiodomalonate Acetaldehyde Dibiphenyl monoiodomalonate.

Diphenanthryl monobromomalonatc.

Dianthracyl monobromomalonate.

Dimethylphenyl monoiodomalonate. piethylphenyl monoehloromalonate. Formaldehyde/ 4 Didecylphenyl monoiodomalonate. H(Pd)/Na0H Didodecylphenyl monobromomalonate. NaCN/NaHCOa Dipentadecylphenyl monochloromalonate. Phosphorous acid K4P207. Di-4-ethy1naphthyl monobromomalonate. Forrnic acid/NaOH Di-4-decylnaphthyl monobromomalonate.

Diphenanthryl dibromomalonate Dianthracyl dibrornomalonate Dimethylphenyl diiodomalonate. Diethylphenyl dichloromalonaj; Didecylphenyl diiodomalonate Didodecylphenyl dibromomalonate Dlpentadecylphenyl dichloromalonate Di-4-ethy1naphthy1 dibromomalonate Di-4-decylnaphthyl dibromomalonate Dibenzyl dibromomalonate KgSgOg/KOH Dibenzyl monobromomalonategp y t yl roma onaten. NaCN/Na0H Diphenylethyl monochloromalonate. lp y pr pyl ii0d0ma10nate. NaCN/NaOH Diphenylpropyl monoiodomalonate. D phenyldodecyl dibromomalonate N aHS/NH OH Diphenyldodecyl monobromomalonate. lphenylhexadecyl diohloromalonate KCN/KOH Diphenylhexadecyl monoehloromalonate. Dibiphenyldecyl dibromomalonate K2S/KOH Dibiphenyldecyl monobromomalonate. Diheptenyl diohloromalonate LiCN/LiOH Diheptenyl monochloromalonate. Didecenyl dibromomalonate Formic aeid/NaHCO Didecenyl monobromomalonate. Di-3,6d0decadionyl diiodomalonate Acetaldehyde Di-3,6-dodecadienyl monoiodomalonate. Dilinolenyl dichloromalonate Na so /NaOH Dilinolenyl monochloromalonate. Dioleyl dichloromalonate. K1SO3/KOI{ Dioleyl monochloromalonate. Dilinoleyl dibr0momalonate Acetaldehyde Dilinoleyl monobromomalonate. Di-7-chlorohexyl dichloroma1onate NaCN [NI-10H Di-7-ch1o1'ohexyl monochloromalonatc.

i-l0-br0m0d0decyl dibromomalongte. Di-lO-bromododecyl monobromomalonate. Di--iodopentadecyl diiodomalonate Phosphorous acid/NmPO Di-15-iodopentadecylmonoiodomalonate. l)i--br0moeicosyl dichloromalonate LizSOg/LiOH Di-ZO-bromoeicosyl monochloromalonate. 1' Dta cyl dibromomalonate NazSzOdNaOH- Di-6,17-dicho1roheptadecyl monobromomalonatv. i-EJ-fiuorononyl diiodomalonate S F Di-9-fiuoronony1monoiodomalonate. Di-4-chloronaphthyl dichloromalonate Di-4-chloronaphthy1monochloromalonate. i-4-br0mobiphenyl dibromomalonate Di-4-bromobipheny1 monobrornomalonate. Di(chloromethy)pheny1 diiodomalonate Di(chloromethy'l)phenyl monoiodomalonate.

Di(br0m0ethyl)phenyl dibromomalonate (NHQHS/NHQH. Di(br0moethyl)phenyl monobromomalonate- Di4(i0d0ethyl)naphthyl diiodomalonate NaI/NH O H Di-4-(iodoethyl)naphthyl monoiodomalonatc.

Di-4-(l0,10-dichlor0decyl)naphthyl dichloromalonate NaCN/NaOII Di-4-(10,IO-dichlorodecyl) naphthyl monochloromalonate.

Di-p-chlorobenzyl dichloromalonate KCN/KOH Di-p-chlorobenzyl monochloromalonate.

Di-o-bromophenylethyl dibromomalonate Di-12-phenyi-6-chl0r0d0decyl dibromomalonate Di-7-chlorohept-2-enyl dichloromalonate Di-3,5,Q-trichlorodecenyl dibromomalonate Di-3,5,Q-trichlorodecenyl monobromomalonato.

. Di-p-nitrobenzyl monobromomalonate.

D1(2-ethyl)hexyl dibromomalonate Di(2-ethyl)hexy1 monobromomalonate.

Di(2-ethy1)hexy1 monoiodomalonate.

Dioctadecenyl monobromomalonate.

Dinaphthyl monoiodomalonate.

. Di(pentadecyl)phenyl monobromomalonatc.

Di(tetmchloro)stearyl monochloromalonatc.

Di(5-iod0)pentadeceny1 monoiodomalonate.

Di(6-chlor0)naphthyl monoiodomalomate.

Dinaphthyl diiodomalonate. Di(pentadecyl)phenyl dibrom Di(tetrachloro)stearyl dichloromalonate Di(5-iodo)pentadecenyl diiodomalonate Di(6chloro)naphthyl diiodomalonate Di(2,3-dibromodecybphenyl dibromomalonat SnClz Di(2,3-dibromodecyDphenyl monobromomalonatc. Di(4,6-dinitro)naphthyl diiodomalonatenu A. Formaldehyde/K0 Di(4,6-dinitro)naphthyl monoiodomalonate Z-ethylhexyl stearyl diiodomalonate NazS/KOH 2-ethylhexyl stearyl monoiodomalouate.

Where A is --PO3R2 and B is CO2R, the trihydrocarbyl nitrophenyl. Hydrocarbyl groups such as alkyL aryl, aralkyl,

dihalophosphonoacetates, as starting materials, are described, alkaryl and alkenyl groups are preferred because of their with the trihydrocarbyl monohalophosphonoacetates being ready availability. Ethyl, propyl, iso-propyl, butyl, pentyl and formed according to equation Ill below: phenyl are especially preferred. X is bromine, chlorine and V iodine. Bromine is preferred.

F reducin a em Specific examples of the trihydrocarbyl III. X-CX A) XCH monohalophosphonoacetates which can be prepared by the C 2 H20 0 00R process of this invention, as schematically described by equav M tion Ill, and specific reducing agents which can be used to ef- R and X are as hereiubefore defined. feet the conversion of the corresponding dihalo derivative are Suitable hydrocarbyl groups or R in the above shown in table lll, e.g., by reaction of the dihalo derivative chlorine, bromine or iodine), suitable reducing agents are sulfide ion in base, thiosulfate ion in base, hydrogen with a noble metal in base, phosphorous acid in base, formaldehyde in base, iodide ion in base, stannous ion, acetaldehyde, formic acid in base, cyanide ion in base, and sulfite ion in base. Preferred reducing agents for use with the dihalomethylenediphosphonates are sulfide ion in base and sulfite ion in base. Where a dibromo-, diiodo-, bromo-chloro, bromoiodo or chloroiodo malonate is the starting material (i.e., where both A and B are -CO,R and one X is chlorine, bromine or iodine and the other X is bromine or iodine), suitable reducing agents are sulfide ion in base, thiosulfate ion in base, hydrogen with a noble metal in base, phosphorous acid in base, formaldehyde in base, iodide ion in base, stannous ion, acetaldehyde, formic acid -in base, and cyanide ion in base, with the preferred reducing agents being stannous ion, sulfide ion in base, and sulfite ion in base. Where thestarting material is a dichloromalonate e.g., where both A and B are CO,R and where both X's are chlorine), suitable reducing agents are sulfite ion in base and cyanide ion in base with sulfite ion in base being preferred. Where the starting material is a dihalophosphonoacetate (i.e., where A is CO R and B is PO;,R and where each X is chlorine, bromine, orjodine I suitable reducing agents are thiosulfate ion in base, hydrogen with a noble metal in base, phosphorous acid in base,formaldehyde in base, stannous ion, acetaldehyde, formic acid in base, and cyanide ion in base, with the preferred reducing agents being stannous ion, su fide ion in base, and sulfite ion in base. A more complete understanding of the nature of the process of this invention and of the reducing agents used in the process of this invention can be obtained from the discussion given hereinafler.

The term reducing agent is used herein to describe those reactants which will cause the conversion of the dihalo derivative to the monohalo derivative according to equation I, II or Ill. It may appear from an examination of these equations that a simple displacement on the bridging carbon atom of one of the halogen atoms by a hydrogen atom occurs. However, upon examination of the reaction products formed from the reducing agents used it will be appreciated that the oxidation state of the reducing agent used has changed and thus an oxidation/reduction reaction has taken place instead of a simple displacement. While not to be bound by theory, the process of this invention can be described in its broadest terms as the reaction of a reactant or starting material which is reduced (the dihalo derivative) during the course of the reaction by a second reactant or starting material which is oxidized (the reducing agent). The oxidation/reduction concepts above described which are involved in the process of this invention are well known to one skilled in the art of oxidation/reduction chemistry and further general discussion in this area is unnecessary. A more specific discussion of the actual reactions involved and the specific reducing agents which can be used in the process of this invention is given hereinafter to facilitate a better understanding of the process of this invention.

The reducing agents which have been described above and are suitable for use in the process of this invention for the reduction of the dihalomethylenediphosphonate, malonate or phosphonoacetate to the monohalo methylenediphosphonate,

malonate or phosphonoacetate are as follows: sulfide ion inv base, sulfite ion in base, thiosulfate ion in base, hydrogen with a noble metal in base, phosphorous acid in base, formaldehyde in base, iodide ion in base, stannous ion, acetaldehyde formic acid in base, and cyanide ion in base.

Where formaldehyde is used as the reducing agent, the

reaction is conducted in basic solution with the reaction product obtained from the reducing agent being the carbonate ion. Where phosphorous acid is used as the reducing agent, the reaction is conducted in basic solution and the phosphorous acid is converted to phosphoric acid. Where cyanide ion is used as the reducing agent, the reaction is run in basic solution with the cyanate ion being produced as a reaction product. Where formic acid-is used as the reducing agent inc) the reaction is run in basic solution with the carbonate ion being produced as a reaction product. Where sulfite ion is used as the reducing agent, the reaction is run in basic solution with the sulfate ion being produced as a reaction product. Where hydrogen is used as the reducing agent, the reaction is run in basic solution (using a noble metal such as palladium, platinum and the like as an electrode) with water being the reaction product. Where the thiosulfate ion is used as the reducing agent the reaction is run in basic solution with the sulfate ion being produced as a reaction product. Where the sulfide ion is used as the reducing agent, the reaction product is free sulfur. Where acetaldehyde is used as the reducing agent, the reaction product is acetic acid. Where stannous ion is used as the reducing agent, the stannic ion is produced as the reaction product. Where the iodide ion is used as the reducing agent, free iodine is formed as the reaction product.

The above described reducing agents and the reaction products produced form the reduction half-reaction, or halfcell, in the process of this invention with the transformation of the dihalo derivatives of the methylene diphosphonates, malonates and phosphonoacetates being the oxidation halfreaction, or half-cell. The use of the above-described halfreaction or half-cells is well-known in oxidation/reduction chemistry. The halfreactions for the reducing agents sitable for use in the process of this invention are described in greater detail in N. A. Langc, Handbook of Chemistry, Revised Tenth Edition, pp. 1223-29, McGraw-Hill Book Company, New York 1967).

Where the reduction half-reaction involves the use of an ionic species, e.g., the sulfite ion or the iodide ion, as the reducing agent, the ionic species can be supplied as a reactant in the process of this invention in the fonn of a water-soluble salt. More specifically any water-soluble species which will provide the appropriate ionic species when dissolved in water is suitable for use in the process of this invention. For the purposes of illustration, the alkali metal salts such as the sodium, potassium .or lithium salts, and the ammonium salts of the ionic species described above as the reducing agents will provide the water-solubility necessary for the formation of the ionic species involved in the reduction of the dihalo derivative to the monohalo derivative. By way of example it can be mentioned, that lithium, sodium, potassium or ammonium iodide will provide the iodide ion where the iodide ion is used as the reducing agent. Similarly the sodium, potassium, lithium or ammonium sulfite, thiosulfate, sulfide, etc., can be used where the sulfite ion, thiosulfate ion or sulfide ion is used as the reducing agent.

Where ostensibly an acid species, e.g., formic acid or phosphorous acid, is used in a basic solution, some neutralization may occur, e.g., resulting in the presence of the formate ion or the phosphite ion. These neutralized" or "partially neutralized" reducing agents, such as sodium formate, sodium phosphite, or sodium dihydrogen phosphite, are also suitable for use in the process of this invention. However, for simplicity in the discussion herein, these species will be described as the acid form used in a basic solution.

All of the ionic species described above as suitable reducing agents are commercially available and one skilled in the art can choose the water-soluble salt which can be advantageously used from an availability and cost standpoint. Organic reducing agents such as formic acid, formaldehyde, and acetaldehyde as well as phosphorous acid and hydrogen (with a noble metal) are also well known reducing agents and are also commercially available.

in some instances the above-described reducing agents are designated as being used in base. With some reducing agents it is not necessary for the reducing agent to be used in basic solution. The reducing agents which are used in basic solution in the process of this invention are sulfide ion, sulfite ion, thiosulfate ion, hydrogen (with a noble metal), formic acid, cyanide ion, phosphorous acid, formaldehyde, and iodide ion. The preparation of the basic solution to be used with these immediately preceding reducing agents can be simply accomplished by the adjustment of the pH of the reaction system through the addition of any water-soluble alkaline material which will not enter into the reaction or complicate the reaction system e.g., hamper purification of the desired reaction product). Suitable such alkaline materials are the alkali metal hydroxides and alkaline earth hydroxides such as sodium hydroxide, potassium hydroxide, lithium hydroxide, magnesium hydroxide and calcium hydroxide. Ammonium hydroxide and basic salts such as Nal-lCO NaC l-l o l(.,lP;O-,, Na PO. and the like are also suitable. Other water-soluble alkaline materials suitable for pH adjustment without departing from i the spirit and scope of this invention can be used. Where the reducing agent is described as being used in base all that is necessary is that the pH of the reaction system be basic. Where a basic reaction system is needed the pH range of the reaction system which is suitable is a pH of from about 7.5 to a pH of about 11, preferably a pH of from about 7.5 to about 9.0. One skilled in the art can select the proportions of alkaline materials to obtain the pH range above described.

Some of the reducing agents listed above do not require the use of a basic solution for the reduction of the dihalo derivative to the monohalo derivative. Examples of these reducing agents are stannous ion and acetaldehyde. Where either of these reducing agents are used, the pH of the reaction system can be essentially neutral, e.g., a pH of from about 6.5 to about 7.5, preferably from about 6.8 to about 7.2.

The amount of reducing agent employed in the process of this invention as described by equations 1, ii and ill above controls the amount of monohalo methylenediphosphonate, malonate or phosphonoacetate formed. The amount of reducing agent used in relation to the amount of dihalo starting material is normally an equivalent amount. The term equivalent amount, as used herein, is intended to embrace the equivalency concept as is used generally in describing changes in the oxidation states of reactants by those skilled in the chemistry of oxidation/reduction processes. In the reduction of the dihalo derivative to the monohalo derivative an oxidation state change of two is involved in the reduction half-reaction. Thus, the oxidation state of the reducing agent (or the active species in the reducing agent) in the oxidation halfreaction must also change by an equivalent amount. More specifically, where sulfide ion in base (oxidation state of 2) is used as the reducing agent the reaction product resulting from the reducing agent is free sulfur (oxidation state of a change in oxidation state of two. Thus, where sulfide ion in base is used as the reducing agent the equivalency ratio is exactly equal to the stoichiometric or equimolar ratio. Most of the reducing agents listed above'as suitable for use in the process of this invention undergo an oxidation state change of two and the equivalent amount of reducing agent will be identical to the stoichiometric amount. Where a reducing agent does not undergo a change of 2 in the oxidation state (between the reactant and product), the equivalent amount will not correspond to the stoichiometric amount but will be in some multiple of the stoichiometric amount, e.g., where the oxidation state change for the reducing agent is only one, twice the stoichiometric amount is needed for the complete conversion of the dihalo derivative to the monohalo derivative, while when, the oxidation state change for the reducing agent is four, only half of the stoichiometric amount is necessary for the conversion of the dihalo derivative to the monohalo derivative. in summary, oxidation state change equivalency of the reducing agent to the dihalo derivative starting material rather than stoichiometric equality or equimolarity is necessary in order to obtain high yields in the reduction of the dihalo methylenediphosphonates, malonates and phosphonoacetates according to the process of this invention. The equivalency ratio of reducing agent to ester is from about 0.9:1 to about 1.1:l, preferably from about 0.95:1 to about 1.05:1. Where less than the above equivalency ratio of reducing agent is used, unreacted dihalo methylenediphosphonate, malonate, or phosphonoacetate remains admixed with the desired monohalo product; on the other hand if the amount of reducing agent used is in excessof the above ratio, some of the monohalo derivative may be further converted to the unhalogenated methylenediphosphonate, malonate or phosphonoacetate, e.g., both of the halogens removed. If a large excess of reducing agent is used substantially all of the dihalo methylenediphosphonate derivative can be reduced to the monohalo derivative and subsequently because of the excess of reducing agent converted to the unhalogenated compound. Highest yields of monohalo methylenediphosphonates, malonates and phosphonoacetates are obtained when essentially equivalent amounts of reducing agent and dihalo derivative are used. As a result a highly preferred embodiment of the process of this invention is to use an exactly equivalent amount of reducing agent, i.e., an equivalency ratio of 1:1. As explained above, to prevent conversion of the monohalo methylenediphosphonate, malonate or phosphonoacetate to the unhalogentated compound, it is preferred that the amount of reducing agent used always be either equal to or less than the amount of reducing agent which would result in equivalency.

Where the above reducing agents are used in the process of this invention to convert the dihalomethylenediphosphonates, malonates and phosphonoacetates to the corresponding monohalo derivatives, one skilled in the art can select appropriate reaction conditions within the guidelines set out hereinbefore to use the reducing agents effectively and to optimize the reaction system and yields obtained for any specific dihalo methylenediphosphonate, malonate or phosphonoacetate reduction. In addition reducing agents other than those specifically described as suitable for use in the process of this invention can be selected based on the disclosure contained herein without departing from the spirit and scope of this invention.

The temperature of the reaction employed in the process of this invention can range from about 25 to about 50 C., preferably from about 10 to about 25 C. The optimum temperature for the reduction of a specific dihalo derivative to the corresponding monohalo derivative by the process of this invention is determined by the size of the hydrocarbyl groups, the particular halogens present in the dihalo derivative and the specific reducing agent used. For example, the smaller the hydrocarbyl group, R, the lower is the optimum reaction temperature; and the lower the atomic number of the halogen the higher is the optimum reaction temperature. Thus, while the reaction can be run at any temperature within the range of 25 to 50 C., the optimum temperature for best yields of the monohalo derivative is somewhat specific but can be readily ascertained by one skilled in the art using the above guidelines. Generally, with temperatures below 25 C. the rate of reaction is so slow as to be impractical. in addition, since the reaction mixture contains water the reaction mixture can become slushy or freeze at temperatures below 25 C. Temperatures above 50 C. should be avoided because of the tendency for undesired side reactions to occur.

The reaction time required for the process of this invention is not a critical aspect because the conversion from the dihalo derivative to the monohalo derivative is essentially instantaneous. Thus, once all of the reducing agent has been added to the reaction mixture, the reduction is substantially complete. Consequently the reaction mixture may be allowed to stand for many hours beyond the time needed for reaction with no adverse effect being noted. However, there is no particular advantage in allowing the reaction mixture to stand longer than required for the reduction of the dihalo compound to the monohalo compound. Generally the reaction time required is from about 15 minutes to about 4 hours, where the process of this invention is run as a batch process. The process of this invention can also be run as a continuous process and the reaction time adjusted accordingly.

The reducing agent is generally added to the dihalo compound as an aqueous solution. The amount of water used in preparing the aqueous solution is not critical. Generally the amount of water used is in a weight ratio to the dihalo coml pound offrom about 1:1 to about :1, preferably 1:1 to 5:1.

A preferred embodiment of this invention is for the dihalo compound to be dissolved in a suitable solvent/water mixture. While the process of this invention can be accomplished without using an added solvent, general process efficiency can be enchanced by the use of a solvent/water mixture. Any low molecular weight organic solvent which is miscible with water, which will dissolve the dihalo ester, and which will not boil off or freeze at the reaction temperature used is suitable. Examples of such solvents are the ethers, amine and alcohols. Among the ether compounds which are suitable as solvents are tetrahydrofuran, dioxane, 1,2-dimethoxyethane, and diethylene glycol dimethyl ether. Suitable amines which can serve as solvents include butylamine, N-methyl butylamine, ethylene diamine, pyridine and morpholine. Methanol, ethanol, propanol, isopropanol and butanol are examples of suitable alcohol solvents. The preferred solvent is methanol. Where a solvent is used, it is generally used in a weight ratio of solvent to ester of from about 10:1 to about 100:1, preferably from about :1 to about 50:1.

For excellent yields of the monohalo methylenediphosphonates, malonates or phosphonoacetates prepared by the process 0 this invention it is preferred that the reducing agent be added in an aqueous solution to the dihalo derivative or, if an added solvent is employed, to the dihalo derivative/solvent mixture. in addition it is preferred that the reducing agent be added slowly with stirring to the dihalo compound. It has been found that if the dihalo compound is added to the reducing agent, a large localized excess of reducing agent is present and as a result any monohalo compound fonned can be immediately reduced to the unhalogenated methylenediphosphonate, malonate or phosphonoacetate. The slow addition of the reducing agent to the dihalo compound coupled with stirring decreases the possibility of a localized concentration of reducing agent occurring and minimizes the reduction to the unhalogenated compound.

After the reaction is complete, the desired monohalo derivative can be separated from the oxidation product of the reducing agent and the solvent/water mixture by using conventional physical separation techniques. The most efficient method to be employed will be dependent on the monohalo derivative prepared and the oxidation product of the reducing agent used. For example, where the sulfide ion in base is used as the reducing agent free sulfur is the oxidation product. The free sulfur can be conveniently removed by filtration. The monohalo compound can be extracted from the filtered solution using chloroform with the chloroform being evaporated off. Correspondingly where iodide ion in base is used as the so reducing agent, iodine is the reaction product and the monohalo derivative can be selectively extracted from the product mixture. One skilled in the art with knowledge of the specific reducing agent (and its oxidation product) used can select the appropriate purification and separation techniques. In general solvent extraction techniques are very useful and preferred separation and purification techniques.

The tetrahydrocarbyl dihalomethylenediphosphonates (C -C dihydrocarbyl dihalomalonates (C,C,,) and trihydrocarbyl dihalophosphonoacetates (C -C as starting materials can be prepared according to the process described in the copending application of Denzel Allan Nicholson, Ser. No. 770,860, filed Oct. 25, 1968, for Process for the Production of Halogenated Methlenediphosphonates, Malonates and Phosphonoacetates, by the hypohalogenation of the corresponding tetrahydrocarbyl methylenediphosphonates, dihydrocarbyl malonates and trihydrocarbyl phosphonoacetates according to the following:

wherein A and B are as hereinbefore defined, wherein OX is a hypohalite ion, e.g., hypochlorite, hypobromite or hypoiodite, and wherein S is an inert, water-miscible organic solvent.

116 The tetrahydrocarbyl alialomethylenediphosphonates (C -C and the trihydrocarbyl dihalophosphonoacetates (C C,) as starting materials can be prepared according to the process described in the copending application of John D.

Curry, Ser. No. 770,805, filed Oct. 25, 1968, for Hypohalogenation of Tetramethyl and Tetraethyl Methylenediphosphonates and Trihydrocarbyl Phosphonoacetates, by the hypohalogenation of the corresponding tetrahydrocarbyl methylenediphosphonates and trihydrocarbyl phosphonoacetates according to the following wherein A and B areas hereinbefore defined (except both A and B are not simultaneously -CO R), wherein OX is a hypohalite ion, e.g., hypochlorite, hypobromite or hypoiodite, wherein M is an electrolyte not containing a halide X that can be displaced by the OX used, and wherein S is an inert, water-immiscible, organic solvent.

The tetrahydrocarbyl dihalomethylenediphosphonates (C -C and the trihydrocarbyl dihalophosphonoacetates (C,C,) as starting materials can be prepared according to the process described in the copending application of Oscar T. Quimby and James B. Prentice, Ser. No. 770,782, filed Oct.

'25, 1968, for Hypohalogenation of Gem-Diphosphonate Esters and Phosphonoacetate Esters, by the hypohalogenation of the corresponding tetrahydrocarbyl methylenediphosphonates and trihydrocarbyl phosphonoacetates according to the following:

wherein A and B are as hereinbefore defined (except both are not simultaneously -C0,R), wherein OX is a hypohalite ion, e.g., hypochlorite, hypobromite or hypoiodite, and wherein M is an added electrolyte.

The dihydrocarbyl dihalomalonates (C -C and the trihydrocarbyl dihalophosphonoacetates (C are commercially available.

The tetrahydrocarbyl methylenediphosphonates, for use in preparing the dihalo derivatives according to the processes described above, can be prepared by reacting dibromomethane with a trihydrocarbyl phosphite, derived from a primary alcohol and phosphorous trichloride. Dibromomethane is a high temperature reactionproduct of methane and bromine. A more detailed discussion of the foregoing appears in US. Pat. No. 3,251,907 of Clarence H. Roy, issued May 17, 1966. The trihydrocarbyl phosphonoacetates can be prepared by the reaction of a trihydrocarbyl phosphite with an a-haloacetic acid ester or they can be purchased commercially. Malonate esters are commercially available.

As mentioned, previously monohalo methylenediphosphonate, malonate and phosphonoacetate esters are useful as synthetic intermediates. For example, the monohalo methylenediphosphonate esters can easily be converted to monohalomethylenediphosphonic acid using conventional hydrolysis techniques. The monohalomethylenediphosphonic acid can be then converted by reaction with strong base to the metal salt of methane 65 hydroxydiphosphonate, a known and valuable detergent builder, according to the following equation:

methane hydroxy diphosmonohalomethyl- 0 phonats (metal salt) enediphos phonic acid Methane hydroxy diphosphonate is disclosed as a detergent builder in US. Pat. No. 3,422,137 Oscar T. Quimby, issued Quimby application also discloses the pyrolysis and the hydrolysis of methylenediphosphonate esters to obtain the water-soluble salts thereof. The methylenediphosphonic acid salts have their principle utility as detergent builders.

The tetrahydrocarbyl monohalomethylenediphosphonates, the dihydrocarbyl monohalomalonates and the trihydrocarbyl monohalophosphonoacetates produced by the process of this invention are useful as extreme pressure additives (where the hydrocarbyl groups have from about one to about 22 carbon atoms) and antiwear additives (where the hydrocarbyl groups have from about six to about 22 carbon atoms) when used in lubricant compositions at the 5 percent level in, e.g., a Kendall base SAE 30 mineral oilas disclosed in the copending application of Robert Earl Wann, Denzel Allan Nicholson, and Ted Joe Logan, Ser. No. 762,966, filed Sept. 26, 1968, for Lubricant Compositions; the copending application of Denzel Allan Nicholson, Ser. No. 770,860, filed Oct. 25, 1968, for Process for the Production of .l-lalogenated Methylene Diphosphonates, Malonates and Phosphonoacetates; the copending applications of Denzel Allan Nicholson, Ser. No. 785,740, filed Dec. 20, 1968, and Ser. No. 795,030 filed Jan. 29, 1969, for Halogenated Phosphonoacetate Esters; and the copending application of Denzel Allan Nicholson, Ser. No. 785,741, filed Dec. 20, 1968, for Methylenediphosophonate Esters. The disclosures of these copending applications are incorporated herein by reference.

The following examples are intended merely to illustrate specific embodiments of the process of this invention. The examples are not intended to limit the invention and one skilled in the art can make appropriate modifications and changes without departing from the spirit and scope of this invention.

EXAMPLE I Preparation of Tetra-iso-propyl Monochioromethylenediphosphonate Sodium hydrosulfide (0.5 mole) was prepared by reacting 0.5 mole of Na s dissolved in 100 cc. of H with 100 cc. of a 37 percent by weight solution of l-lCl. After the HC! addition was completed, the solution, which had a pH of about 8-9, was placed in a one liter addition flask and added slowly to a solution of tetra-iso-propyl dichloromethylenediphosphonate (0.5 mole) in 200 cc. of methanol. An ice bath was used to maintain the temperature at about 25 C. during the addition. After the addition was completed the temperature was raised to 50 C. and maintained there for a 2 hour period. The solution was then extracted with several portions of Cl-iCl The sulfur formed was filtered oh and the Cl-iCl, was evaporated off. The oil which remained was refiltered and run through a chromatographic column filled with alumina. ="P nmr indicated a 95 percent yield of tetra-iso-propyl monochloromethylenediphosphonate.

EXAMPLE ll Preparation of Tetra-iso-propyl Monobromomethylenediphosphonate Sodium hydrosulfide (0.5 mole) was prepared as in example 1 above. The solution of sodium hydrosulfide was placed in a one liter addition flask and added slowly to a solution of tetraiso-propyl dibromomethylenediphosphonate (0.5 mole) in 200 cc. of methanol. During the addition the temperature was maintained at 25 C. A solid, believed to be sulfur, immediately formed. The solution was stirred at room temperature for 1-% hours and the reaction mixture was allowed to stand overnight. The following morning the temperature was slowly increased to 50 C. After 2 hours the solid sulfur was filtered off and the filtered solution was extracted three times with CHCl The CHCI, layer was dried over anhydrous sodium sulfate, refiltered, and evaporated down. The oil which remained was refiltered and run through a chromatographic column filled with alumina. "P' nmr'revealed an 82 percent yield of tetra-iso-propyl Sodium hydrosulfide (0.396 mole) was prepared by reacting 0.396 mole of Na s dissolved in 200 cc. of H 0 with cc. of an aqueous solution containing 0.396 mole of HCl. The

. solution, having a pH of about 8-9, was placed in a 500 cc. ad-

dition funnel and added dropwise to tetra-iso-propyl dichloromethlenediphosphonate dissolved in 600 cc. of a methanol/water (1:1) solution. During the addition the temperature was maintained at about 18 C. when the addition was complete the solution was heated, at 50 C., for 3 hours. The sulfur formed was filtered off. The remaining solution was extracted three times with Cl-lCl and dried overnight over anhydrous sodium sulfate. The solution was filtered and the chlorofonn evaporated off. The remaining oil was then distilled. "P nmr revealed an 88 percent yield of tetra-isopropyl monochloromethylenediphosphonate.

When in the above example other solvents are substituted for the methanol used above on an equivalent basis, similar results are obtained in that tetra-iso-propyl monochloromethylenediphosphonate is prepared, e.g., solvents such as tetrahydrofuran, dioxane, 1,2-dimethoxyethane, diethylene glycol dimethyl ether, butylamine, N-methyl butylamine, ethylenediamine, pyridine, morpholine, methanol, ethanol, propanol, iso-propanol and butanol. Substantially similar results are obtained, when in the above example, the methanol is used in a weight ratio of methanol to tetra-Isopropyl dlchloromethylenedlphosphonate of 10:1 to about 100:1.

EXAMPLE lV Preparation of Tetra-iso-propyl Monoiodomethylenediphosphonate Sodium hydrosulfide (0.1 mole) is prepared by reacting 0.1 moles of Na,S dissolved in 200 cc. of l-i,0 with 100 cc. aqueous solution of HCl (0.1 mole). The solution of pH 8-9 is placed in a 500 cc. addition funnel and added dropwise to 0.1 mole of tetra-iso-propyl diiodomethylenediphosphonate dissolved in 200 cc. of methanol. During the addition the temperature is maintained at 20 C. When the addition is completed the solution is maintained at 20 C. and stirred for 1 hour. The sulfur is then filtered ofi'. The remaining solution is extracted three times with CHCl and dried over anhydrous sodium sulfate for 20 minutes. After evaporation of the CHCl,, tetra-iso-propyl mon0iodomethylenediphosphonate is obtained.

EXAMPLE V Preparation of Triethyl Monochlorophosphonoacetate To a stirred solution of triethyl dichlorophosphonoacetate (0.245 mole) in 200 cc. of methanol was added a solution consisting of 30.8 of sodium sulfite (0.50 mole) and 41 g. of sodium bicarbonate (0.50 mole) in 200 cc. of water. The temperature of the reaction solution was maintained at 20 C. during the addition. Extraction with Cl-lCl removed the product which, after removal of the chloroform, was shown by gas chromatography to be 97.7 percent pure triethyl monochlorophosphonoacetate.

Substantially similar results are obtained when in the above example other water-soluble alkaline materials are substituted on an equivalent basis for the sodium bicarbonate used above in that triethyl monochlorophosphonoacetate. is prepared,

e.g., water-soluble alkaline materials such as the alkali metal hydroxides, e.g., sodium hydroxide, potassium hydroxide,

lithium hydroxide, the alkaline earth hydroxides, e.g., calcium.

hydroxide and magnesium hydroxide, ammonium hydroxide, sodium acetate, potassium pyrophosphate and sodium orthophosphate. Substantially similar results are also obtained when in the above example the pH of the reaction system ranges from about 7.5 to about 11.0 in that triethyl monochlorophosphonoacetate is prepared.

EXAMPLE Vl Preparation of Triethyl Monobromophosphonoecetate EXAMPLE VII Preparation of Diethyl Monobromomalonate Fifteen grams of diethyl dibromomalonate (0.047 mole) was dissolved in 400 cc. of methanol at C. A slurry of 0.5 mole of SnF, in 100 cc. of a 50/50 mixture of methanol/water was slowly added. The mixture was stirred for minutes and workup of the reaction mixture by extraction with CHCl; gave a product which was shown by chromatographic analysis to be 97 percent pure diethyl monobromomalonate.

EXAMPLE Vlll Preparation of Tetra-iso-propyl Monobromomethylenediphosphonate The procedure used in example Vll above was followed except that stannous chloride was substituted for the stannous fluoride and tetra-iso-propyl dibromomethylenediphosphonate was substituted for the diethyl dibromomalonate used. On analysis of the product an 84 percent yield of tetra-iso-propyl monobromomethylenediphosphonate as shown by P nmr was obtained.

EXAMPLE IX Preparation of diethyl monochloromalonate The procedure used above for example V was repeated except that diethyl dichloromalonate was substituted for the triethyl dichlorophosphonoacetate used and the reaction temperature was changed to 25 C. On workup of the reaction product mixture an 81.5 percent yield of diethyl monochloromalonate as determined by gas chromatographic analysis was obtained.

EXAMPLE X Preparation of tetra-iso-propyl monochloromethylenediphosphonate The procedure used above for example V was repeated except that tetra-iso-propyl dichloromethylenediphosphonate was substituted for the triethyl dichlorophosphonoacetate used. The reaction product mixture was worked up by distillation and essentially pure tetra-iso-propyl monochloromethylenediphosphonate was obtained.

EXAMPLE X1 Preparation of Tetra-iso-propyl Monobromomethylenediphosphonate A solution of sodium cyanide (24.5 g. 0.5 mole) in 50 cc. of water was added slowly to a solution of tetra-iso-propyl dibromomethylenediphosphonate (251.0 g., 0.5 mole) in 200 cc. of methanol. The temperature was kept between 25-30 C. throughout the reaction. The reaction was very exothermic during addition. After addition .was complete the solution was allowed to stir for 2 hours and then extracted with chloroform. The organic layer was collected and dried and removal of the solvent left a colorless liquid. A phosphorus nmr of this liquid showed, tetra-iso-propyl monobromomethylenediphosphonate was obtained.

EXAMPLE Xll Preparation of Tetra-iso-propyl Monobromomethylenediphosphonate A solution of stannous chloride (dihydrate) (99.3 g., 0.5 mole) in 50 cc. of water was added slowly to a solution of tetra-iso-propyl dibrornomethylenediphosphonate (251.0 g., 0.5 mole) in 1500 cc. of methyl alcohol. The temperature was kept at 20 C. with an ice bath after an initial exothermic surge to 40 C. After addition was complete the solution was allowed to stir for 30 minutes and then extracted with chloroform, the organic layer collected and dried. Removal of the solvent left tetraiso-propyl monobromomethylenediphosphonate.

EXAMPLE Xlll Preparation of tetra(decyl) Monochloromethylenediphosphonate Sodium hydrosulfide (0.5 mole) is prepared by reacting 0.5 mole of Na,S dissolved in cc. of H,O with 100 cc. of a 37 percent by weight solution of HCI. After the HCl addition is completed, the solution, having a pH of about 89, is placed in a 1 liter addition flask and added slowly to a solution of tetra(decyl) dichloromethylenediphosphonate (0.5 mole) in 200 cc. of methanol. An ice bath is used to maintain the temperature at about 25 C. during the addition. After the addition is completed the temperature is raised to 50 C. and maintained there for a 2 hour period. The solution is then extracted with several portions of CHCI, The sulfur formed is filtered off and the CHCl, is evaporated off. The oil which remains is refiltered and run through a chromatographic column filled with alumina. Tetra( decyl) monochloromethylenediphosphonate is prepared.

EXAMPLE XlV Preparation of Tetrapentyl Monobromomethylenediphosphonate Sodium hydrosulfide (0.5 mole) is prepared by reacting 0.5 mole of Na,S dissolved in 100 cc. of H 0 with I00 cc. of a 37 percent by weight solution of HCl. After the HCl addition is completed, the solution, having a pH of about 8-9, is placed in a 1 liter addition flask and added slowly to a solution of tetrapentyl dibromomethylenediphosphonate (0.5 mole) in 200 cc. of methanol. An ice bath is used to maintain the temperature at about 25 C. during the addition. After the addition is completed the temperature is raised to 50 C. and maintained there for a 2 hour period. The solution is then extracted with several portions of CHCl The sulfur formed is filtered oh and the CHCl is evaporated ofi. The oil which remains is refiltered and run through a chromatographic column filled with alumina. Tetrapentyl monobromomethylenediphosphonate is prepared.

EXAMPLE XV To a stirred solution of triphenyl diiodophosphonoacetate (0.245 mole) in 200 cc. of methanol is added a solution consisting of 30.8 g. of sodium sulfite (0.50 mole) and 41 g. of sodium bicarbonate (0.50 mole) in 200 cc. of water. The tem-- perature of the reaction solution is maintained at 20 C. during the addition. Extraction with CI'ICI is used to remove the product which, after the chloroform is removed, is triphenyl monoiodophosphonoacetate.

EXAMPLE XVI Preparation of Tri( 2-chloro)ethyl Monobromophosphonoacetate Tri(2-chloro)ethyl dibromophosphonoacetate (0.026 mole) is dissolved in 100 cc. of a 50/50 mixture of water and methanol and the solution is colled to C. A slurry of stannous fluoride (mole) in Mole) in methanol (50 cc.) is slowly added to the solution. After these combined solutions are stirred for min., 50 cc. of water is added. The reaction mixture is worked up after minutes by CHCl extraction. Removal of the organic solvents results in nearly pure tri( 2- chloro)ethyl monobromophosphonoacetate.

EXAMPLE XVII Preparation ofDinenzyl Monobromomalonate The procedure used in example V above is repeated except that dibenzyl dibromomalonate is substituted for the triethyl dichlorophosphonoacetate used and the reaction temperature is changed to 25 C. 0n workup of the reaction product mixture, dibenzyl monobromomalonate is obtained.

EXAMPLE XVIII Preparation of Tetrapentenyl Monobromomethylenediphosphonate A solution of stannous chloride (dihydrate) (0.5 mole) in 50 cc. of water is added slowly to a solution of tetrapentenyl dibromomethylenediphosphonate (0.5 mole) in 1500 cc. of methyl alcohol. The temperature is kept at C. with an ice bath. After addition is complete the solution is allowed to stir for 30 minutes and then extracted with chloroform, the organic layer collected and dried. Solvent removal affords tetrapentenyl monobromomehtylenediphosphonate.

EXAMPLE XIX Preparation of Tetranitrophenyl Monobromomethylenediphosphonate Sodium hydrosulfide (0.5 mole) is prepared by reacting 0.5 mole of Na S dissolved in 100 cc. of H 0 with 100 cc. of a 37 percent by weight solution of HG]. After the HCl addition is completed, the solution, having a pH of 8-9, is placed in a 1 liter addition flask and added slowly to a solution of tetranitrophenyl dibromomethylenediphosphonate (0.5 mole) in 200 cc. of methanol. An ice bath is used to maintain the temperature at about C. during the addition. After the addition is completed the temperature is raised to 50 C. and maintained there for a 2 hour period. The solution is then extracted with several portions of CHCl The sulfur formed is filtered off and the CI'ICl is evaporated 0E. Tetranitrophenyl monobromomethylenediphosphonate is obtained.

EXAMPLE XX Preparation of Di(methyl)phenyl Monobromomalonate The procedure used in example V above is repeated except that di(methyl)phenyl dibromomalonate is substituted forthe triethyl dichlorophosphonoacetate used and the reaction temperature is changed to 25 C. On workup of the reaction product mixture di(methyl)phenyl monobromomalonate is obtained.

EXAMPLE XXI Preparation of Tetra( chloro )phenyl Monochloromethylenediphosphonate Sodium hydrosulfide (0.5 mole) is prepared by reacting 0.5 mole of Na s dissolved in cc. of H 0 with 100 cc. of a 37 percent by weight solution of HCl. After the HCl addition is completed, the solution, having a pH of 89, is placed in a one liter addition flask and added slowly to a solution of tetra(chloro)phenyl dichloromethylenediphosphonate (0.5 mole) in 200 cc. of methanol. An ice bath is used to maintain the temperature at about 25 C. during the addition. After the addition is completed the temperature is raised to 50 C. and maintained there for a 2 hour period. The solution is then extracted with several portions of CI-ICl The sulfur formed is filtered off and the CHCl is evaporated off. Tetra(chloro)phenyl monochloromethylenediphosphonate is obtained.

EXAMPLE XXII Preparation of Tri( chloromethyl )phenyl Monochlorophosphonoacetate Sodium hydrosulfide (0.5 mole) is prepared by reacting 0.5 mole of Na s dissolved in I00 cc. of H 0 with 100 cc. of a 37 percent by weight solution of HCl. After the HCl addition is completed, the solution, having a pH of 8-9, is placed in a 1 liter addition flask and added slowly to a solution of tri(chloromethyl)phenyl dichlorophosphonoacetate (0.5 mole) in 200 of methanol. An ice bath is used to maintain the temperature at about 25 C. during the addition. After the addition is completed the temperature is raised to 50 C. and maintained there for a 2 hour period. The solution is then extracted with several portions of CHCI The sulfur formed is filtered off and the CHCl is evaporated off. Tri(chloromethyl)phenyl monochlorophosphonoacetate is prepared.

EXAMPLE XXIII Preparation of Di( chloro )benzyl Monobromomalonate A solution of stannous chloride (dihydrate) (0.5 mole) in 50 cc. of water is added slowly to a solution of di(chloro)benzyl dibromomalonate (0.5 mole) in 1500 cc. of methyl alcohol. The temperature is kept at 20 C. with an ice bath. After addition is complete the solution is allowed to stir for 30 minutes and then extracted with chloroform, the organic layer collected and dried. Removal of the solvent affords di(chloro)benzyl monobromomalonate.

EXAMPLE XXIV Preparation of Di(chloro)decenyl Monobromomalonate Sodium hydrosulfide (0.5 mole) is prepared as in example I above. The solution of sodium hydrosulfide is placed CHCI 1 liter addition flask and added slowly to a solution of di(chloro)decenyl dibromomalonate (0.5 mole) in 200 cc. of methanol. During the addition the temperature is maintained at 25 C. The solution is stirred at room temperature for 1-52 hours and the reaction mixture is allowed to stand overnight. The temperature is then slowly increased to 50 C. After 2 hours solid sulfur is filtered off and the filtered solution is extracted three times with CI'ICl The CI-ICL layer is dried over anhydrous sodium sulfate, refilter ed, and evaporated down.

Di(chloro )decenyl monobromomalonate is obtained.

Other tetrahydrocarbyl dihalomethylenediphosphonates,

such as those described in column (A) of table I, can be substituted on an equivalent basis for the tetrahydrocarbyl dihalomethylenediphosphonates used in examples I-IV, VIII, X-XIV, XVIII, XIX and XXI above, and other reducing agents, such at those described in column (B) of table I, can be substituted on an equivalent basis for the reducing agents used in examples I-IV, VIII, X-XIV, XVIII, XIX and XXI above with substantially similar results in that other tetrahydrocarbyl monohalomethylenediphosphonates, such as those shown in column (C) of table I, are obtained.

Other dihydrocarbyl dihalomalonates, such as those described in column (A) of table II, can be substituted on an equivalent basis for the dihydrocarbyl dihalomalonates used in examples VII, IX, XVII, XX, XXIII, and XXIV above and other reducing agents, such as those described in column (B) of table II can be substituted on an equivalent basis for the reducing agents used in examples VII, IX, XVII, XX, XXIII, and XXIV above with the proviso that sulfite ion in base and cyanide ion in base is used with the dichloromalonates) with substantially similar results in that other dihydrocarbyl monohalomalonates, such as those shown in column (C) of table II, are obtained.

Other trihydrocarbyl dihalophosphonoacetates, such as those described in column (A) of table III, can be substituted on an equivalent basis for the trihydrocarbyl dihalophosphonoacetates used in examples V, VI, XV, XVI, and XXII above and other reducing agents, such as those described in column (B) of table III, can be substituted on an equivalent basis for the reducing agents used in examples V, VI, XV, XV, and XXII above with substantially similar results in that other trihydrocarbyl monohalophosphonoacetates, such as shown in column (C) of table III, are obtained.

The terminology, e.g., methylenediphosphonate (C -C malonates (C -C and phosphonoacetates C -C is used herein to describe the carbon content of the ester groups present in the methylenediphosphonates, malonates and phosphonoacetates.

What is claimed is:

l. (twice amended) A process for the preparation of monohalo methylenecliphosphonates, and phosphonoacetates, comprising reacting an ester of the fonnula A XaLX wherein A is selected from the group consisting of PO R, and -CO,R, wherein each R is a hydrocarbyl group selected from the group consisting of alkyl, haloalkyl, alkenyl, haloalkenyl and unsubstituted aryl, alkaryl, aralkyl, haloaryl, haloalkaryl, haloaralkyl, and nitroaryl groups having from one to about 22 carbon atoms, and wherein each X is a halogen atom selected from the group consisting of chlorine, bromine and iodine; with a reducing agent, selected from the group consisting of sulfide, thiosulfate, iodide, cyanide and sulfite compounds in base, said compounds being capable of producing respectively the sulfide, thiosulfate, iodide, cyanide and sulfite ions in said base, hydrogen with a nobel metal in base, phosphorous acid in base, formic acid in base, formaldehyde, acetaldehyde, and stannous compounds capable of producing stannous ion, said base being one which is compatible with the reaction system the equivalency ratio of reducing agent to ester being from about 0.9:l to about 1.111, said reducing agent being selected as followsf 1. when A is PO R the reducing agent is selected from the group consisting of said sulfide compounds in said base, said sulfite compounds in said base, said thiosulfate compounds in said base, hydrogen with a noble metal in said base, formic acid in said base, said cyanide compounds in said base, phosphorous acid in said base, said iodide compounds in said base and formaldehyde in said base; and

. when A is CO R the reducing agent is selected from the group consisting of said stannous compounds, acetaldehyde, said sulfide compounds in said base, said sulfite compounds in said base, said thiosulfate compounds in said base, hydrogen with a noble metal in said base, formic acid in said base, said cyanide compounds in said base, phosphorous acid in said base, and formaldehyde in said base;

said process being conducted in aqueous solution at a temperature of from about 25 to about 50 C.

2. The process of claim 1 wherein the aqueous solution contains additionally a low molecular weight organic water-miscible solvent in a weight ratio of solvent to the ester of claim I of from about l0:l to about :l.

3. The process of claim 2 wherein the solvent is selected from the group consisting of tetrahydrofuran, dioxane, 1,2- dimethoxyethane, diethylene glycol dimethyl ether, butylamine, N-methyl butylamine, ethylenediamine, pyridine, morpholine, methanol, ethanol, propanol, iso-propanol and butanol.

4. (amended) The process of claim 1 wherein the equivalency ratio is 1:1.

5. The process of claim 1 wherein the reducing agent is selected from the group consisting of sulfide, thiosulfate, sulfite and cyanide compounds of claim 1 in base hydrogen with a noble metal in base, phosphorous acid in base, formaldehyde in base, and formic acid in base, said base being the base of claim I and wherein the aqueous solution has a pH of from about 7.5 to about 1 l.

6. The process of claim 5 wherein the aqueous solution has a pH of from about 7.5 to about 9.0.

7. The process of claim 1 wherein the reducing agent is selected from the group consisting of a stannous compound of claim I, and acetaldehyde, and wherein the aqueous solution has a pH of from about 6.5 to about 7.5.

8. The process of claim 7 wherein the aqueous solution has a pH offrom about 6.8 to about 7.2.

9. The process of claim 1 wherein A is PO R wherein R is selected from the group consisting of alkyl, alkenyl, and unsubstituted aryl, aralkyl, and alkaryl groups, and wherein X is bromine.

10. The process of claim 9 wherein the reducing agent is selected from the group consisting of sulfide and sulfite compounds in base, said compounds being capable of producing, respectively, the sulfide and sulfite ions in said base, and said base being compatible with the reaction system.

11. The process of claim 10 wherein R is selected from the group consisting of ethyl, propyl, iso-propyl, butyl and pentyl.

12. The process of claim 10 wherein R is an alkyl group having from six to 22 carbon atoms.

13. The process of claim 9 wherein R is phenyl.

14. The process of claim I wherein A is CO,R wherein R is selected from the group consisting of alkyl, alkenyl and unsubstituted aryl, aralkyl, and alkaryl groups, and wherein X is bromine.

15. The process of claim 14 wherein the reducing agent is selected from the group consisting of sulfide and sulfite compounds in base, said compounds being capable of producing, respectively, the sulfide and sulfite ions in said base, and stannous compounds capable of producing stannous ions, said base being compatible with the reaction system.

16. The process of claim 15 wherein R is selected from the group consisting of ethyl, propyl, iso-propyl, butyl and pentyl.

17. The process of claim 15 wherein R is an alkyl group having from six to 22 carbon atoms.

18. The process of claim 14 wherein R is phenyl.

'l' t I i 

2. when A is -CO2R the reducing agent is selected from the group consisting of said stannous compounds, acetaldehyde, said sulfide compounds in said base, said sulfite compounds in said base, said thiosulfate compounds in said base, hydrogen with a noble metal in said base, formic acid in said base, said cyanide compounds in said base, phosphorous acid in said base, and formaldehyde in said base; said process being conducted in aqueous solution at a temperature of from about -25* to about 50* C.
 2. The process of claim 1 wherein the aqueous solution contains additionally a low molecular weight organic water-miscible solvent in a weight ratio of solvent to the ester of claim 1 of from about 10:1 to about 100:1.
 3. The process of claim 2 wherein the solvent is selected from the group consisting of tetrahydrofuran, dioxane, 1,2-dimethoxyethane, diethylene glycol dimethyl ether, butylamine, N-methyl butylamine, ethylenediamine, pyridine, morpholine, methanol, ethanol, propanol, iso-propanol and butanol.
 4. The process of claim 1 wherein the equivalency ratio is 1:1.
 5. The process of claim 1 wherein the reducing agent is selected from the group consisting of sulfide, thiosulfate, sulfite and cyanide compounds of claim 1 in base hydrogen with a noble metal in base, phosphorous acid in base, formaldehyde in base, and formic acid in base, said base being the base of claim 1 and wherein the aqueous solution has a pH of from about 7.5 to about
 11. 6. The process of claim 5 wherein the aqueous solution has a pH of from about 7.5 to about 9.0.
 7. The process of claim 1 wherein the reducing agent is selected from the group consisting of a stannous compound of claim 1, and acetaldehyde, and wherein the aqueous solution has a pH of from about 6.5 to about 7.5.
 8. The process of claim 7 wherein the aqueous solution has a pH of from about 6.8 to about 7.2.
 9. The process of claim 1 wherein A is -PO3R2, wherein R is selected from the group consisting of alkyl, alkenyl, and unsubstituted aryl, aralkyl, and alkaryl groups, and wherein X is bromine.
 10. The process of claim 9 wherein the reducing agent is selected from the group consisting of sulfide and sulfite compounds in base, said compounds being capable of producing, respectively, the sulfide and sulfite ions in said base, and said base being compatible with the reaction system.
 11. The process of claim 10 wherein R is selected from the group consisting of ethyl, propyl, iso-propyl, butyl and pentyl.
 12. The process of claim 10 wherein R is an alkyl group having from six to 22 carbon atoms.
 13. The process of claim 9 wherein R is phenyl.
 14. The process of claim 1 wherein A is -CO2R wherein R is selected from the group consisting of alkyl, alkenyl and unsubstituted aryl, aralkyl, and alkaryl groups, and wherein X is bromine.
 15. The process of claim 14 wherein the reducing agent is selected from the group consisting of sulfide and sulfite compounds in base, said compounds being capable of producing, respectively, the sulfide and sulfite ions in said base, and stannous compounds capable of producing stannous ions, said base being compatible with the reaction system.
 16. The process of claim 15 wherein R is selected from the group consisting of ethyl, propyl, iso-propyl, butyl and pentyl.
 17. The process of claim 15 wherein R is an alkyl group having from six to 22 carbon atoms.
 18. The process of claim 14 wherein R is phenyl. 